Single-phase motor.



S. R. BERGMAN.

SINGLE PHASE MOTOR.

APPLIOATIOK Hum nun: 6,1908.

924,725. Patented June 15, 1909.

Witnesses: 5 Inventor Sven R. Bergman was, b m

SVEl l Rt BERGMAN, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELEGlRIOCO1 EPANY, A GOREORATION OF NEW YORK SENGLE-PZEASE M65303.

Applicafien filed June 5, 3.9%.

To all? "whom it Be it irnovm that l, SvnN BERGMAN, a subject of theKing of Sweden, residing at Lynn, in the county ofEsseX, State of Massa-5 chusetts, have invented certain new and usei'ul improvements inSingle-Phase Motors, of which. the following is a specification.

My invention relates to single-phase inotors oftre induction type havingself-starting characteristics.

One Well known arrangement for rendering a single-phase motorself-starting consists in providing the primary member with a mainwinding and a starting Winding displaced from each other; the mainwinding being of comparatively high reactance and low resistance, andthe starting winding of low reactance and high resistance. The startingWinding ordinarily has a large number of turns, an d is Wound withsmaller wire than the main winding, and, in addition, in order to givethe windings diiierent reactances per turn, the slots containing the twowindings have sometimes been of different shape. Such a 2.5 constructionhas the disadvantage that the number of poles is fixed by thearrangement of slots, so that the same primary member cannot be used formotors of different num bers of oles. By my invention I am enabled so toobtain the same results as though the slots Were of different shapes,and yet .mploy uniform slots, so that the same stator may be used fordifierent pole numbers.

My lnvention consists in arrangine the stator with open slots, placingthe main Winding in certain of the slots and the starting Winding in theremaining slots, and employing magnetic Wedgesto close the slotsoccupied by the main winding, and non- 40 magnetic Wedges for the slotscontaining the starting winding! Since the starting Winding is Woundwith smaller wire-than the main winding, the cross-section of the coilsof the starting winding ma; sometimes be less than the cross-section ofthe slots. In such a case, my invention further consists in arrangingthe coils of the starting winding in the tops of the slots filling thebottoms of the slots with pieces of wood or other non-magnetic material,there by further decreasing-the reactance' of the starting-winding. V

My invention Will bestbe understood by reference to the acconi znyingdrawings, in

fepecification of Letters Patent.

they occupy, and

Figure i shows an end view, iartl y in cross-sectimi, of the primarymember of a single-phase induction motor arranged in accordance with myinvention, and Fig; 2 is a diagram of the connections of the windings ofthe primary member.

In the drawings, it represents the stator, which as usual iscoi'i'structed of laminations, and which is formed with uniform openslots. In certain of these slots, the coils B of the main winding areplaced, and in the remaining slots are the coils C of the startingwinding. These latter coils are of smaller wire than the main coils, andconsequently have higher resistance. The containing the main winding Bare closed with wedges b, of magnetic material. These wedges, which maybe constructed of wire gauze disclosed in my former patent;- lio. 572324.2, issued December 3, 1907, forn'i a path of low reluctance for thellux or the main winding, and, consequently, this win ing a highreactance. The wedges c, oi the slots occupied hy the starting winding,are made of non-magnetic material, such as wood. The coils (J are placedin the tops of the slots, and the bottoms of tie slots are iilled bypieces of wood, or other non-magnetic niaterial, cl. This arrangement ofthe coils of the starting winding g" them a compara-v tively lowreactance. Furthermore, since all the slots are uniform, the number ofpoles is not "fixed, but the same laminations may be employed for motorsof different pole-numbers.

Fig. 2 shows the connections ofthe windings, the main winding 2% andstarting winding C are connect-ed in parallel. D represents thesecomlary member, which is indicated diagrammatically as of the squirrelca type, E rcpr scnts a switch for opening; t circuit of the startingwinding; alter th motor isup to speed, and i represents the supplyconducti'irs for the motor.

do not desire to limit mysell to the par ticular constructirm andarri'uigcment 0 parts here shown, but aim in the appended claims toCOYGY all modifications which are within the scope of my invention.

ll l'litli I claim as new and desire to sou e by Letters Patent of theUnited States.

i. in a single-plume induction motor, a primary member formed with. openslots, :1 low-resistance main winding distributed in certain of saidslot a higirresistance stark if i Cir

ilifa netic means for filling the bottoms of the latter slots, wedges ofmagnetic material closing the slots occupied by the main winding, andWedges of non-magnetic material for the'slots occu ied by the startingwinding.

In witness w ereof, I have hereunto set my hand this third day of June,1908.

' SVEN R. BERGMAN.

ing winding in the rei'nanin slots',wedges of magnetic material closingt e slots occupied by the main winding, and wedges of non magneticmaterial for the slots occupied by 5 the starting winding.

' 2. In a single hase'induction motor, a primary i-iember termed withuniform open slots, a low-resistance main winding distributed inandfilling certain of said slots, a high-resistance starting windinglocated in the topsv of the remaining slots, non-mag- V Witnesses? JOHNA. McMANUs, Jr., CHAnLns A. BARNARI

